WORCESTER — Tuesday at 3:45 p.m., the medieval castle doors of the Higgins Armory Museum are to close for the last time. Three generations of the Higgins family will be present for the occasion.

The collection is moving to the Worcester Art Museum, and the building is being sold.

Clarinda "Rindy" Higgins, granddaughter of the museum's founder, John Woodman Higgins, said it is the last opportunity to thank her grandfather, whose vision inspired generations of young men and women, provided a resource for scholars and fascinated people of all ages.

"Unfortunately, closing the museum means closing the book on an important part of Worcester's industrial heritage," said Ms. Higgins, who is a Worcester native and lifetime incorporator of the Higgins Armory Museum.

Though she and husband, William G. Armstrong Jr., live in Westport, Conn., the couple often visits their one-room post-and-beam cabin in Brookfield that was once owned by her grandfather. Ms. Higgins said she and her husband have deep connections in Worcester.

"I'm a Bancroft School girl and have fond memories of Worcester," she said. "I haven't turned my back on it."

She said she recently asked her deceased grandfather for direction on what should happen to the glass and steel icon on Barber Avenue.

"I asked him to speak to me and he said it is an opportunity," she said. "I'm not sure what that opportunity is, but he said to do something new and innovative — not let it go dusty or tear it down."

Ms. Higgins said she would love to see the building reused in an exciting, vibrant way that would add to the culture of Worcester. A committee formed to determine the building's fate, she said, was narrowly focused and she is concerned trustees will expedite the sale to send money quickly to the Worcester Art Museum.

Its placement on the National Register of Historic Places does not necessarily protect the building from demolition, she added.

"I would hate to see such an innovative place disappear," she said. "It is a landmark site coming into Worcester and dramatic to see on the hill."

Ms. Higgins said she sees the building possibly repurposed as a hotel or a restaurant, but understands challenges for a new owner would be heating and cooling the immense structure.

"My grandfather was such an innovative thinker he would have made it the first of the next-generation of things and used cutting-edge solar and use of mirrors to reflect light to cut down on electricity costs," she said. "The building itself stands for history and innovation at the same time. I can see my grandfather looking down and saying, 'Reinvent it.' Worcester could use a shot in the arm and sparkle there with something that is culturally appealing."

Her husband agrees and understands the complexities involved, but sees moving the collection as a great loss.

"No one knows how to use that purpose-built structure," Mr. Armstrong said. "And you can't learn this kind of thing in any other context. The curators and others at the museum know what they are doing and have done it so well for so long and there is so much history built into this place, it is literally impossible to replicate that in any other venue.

"The Worcester Art Museum will do its best to exhibit part of the collection they are taking and put a lot of it on display, but no matter what anyone does with the pieces that constitute the collection, it won't ever look like it did in the context of the great castle building on Barber Avenue."

He said he likes to think of it as a line from "Camelot."

"Don't let it be forgot, once there was a spot, for one brief shining moment, that was known as … the Higgins Armory Museum," he said.

"For us, the loss of this museum is also personal," Ms. Higgins added. "As a child, I celebrated so many wonderful holidays here with my grandparents and our big extended family. On the last day of this museum, we wouldn't want to be anywhere else."

Two of founder John Woodman Higgins' great-grandsons and three of his great-great-grandchildren will also be taking their final tour of the iconic collection Tuesday.